Puget Serenity i7 PC System

SPCR Certified Silent PCs | Complete|Mobile Systems
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ACOUSTIC & THERMAL CHARACTERISTICS

This is the core of the SPCR certification for a PC. Many tools were used to analyze the system:

The basic approach is to assess the noise, thermal and power characteristics at idle, and then at full CPU and GPU loads. The testing was conducted entirely in the SPCR anechoic chamber, with the door open to ensure adequate room ventilation when noise measurements or recordings were not being performed.

Test Results: Customized Puget Serenity PC
Criteria
idle
1080p play
Prime95
Prime95+
Furmark
AC power
70W
80~86W
173~180W
232~240W
CPU
28°C
35~37°C
55°C
55°C
GPU
33°C
40~42°C
44°C
68°C
Mainboard
30°C
35~37°C
35°C
55°C
HDD
26°C
26°C
26°C
27°C
SPL - dBA@1m
14
18
18
18
SPL - ISO 7779 Seated User Position
16
20
20
20
Ambient conditions: 20°C, 10 dBA - Sleep Mode Power: 3.4W
Max safe temps - CPU: >80°C, GPU: >90°C, HDD: >55°C

1. Noise

This is a very quiet computer system. The measured sound pressure level of just 14 dBA@1m at idle and 18 dBA after an hour at full system load is about as low as we've measured. The ISO 7779 computer noise standard's defined "Seated User Position" SPL places the microphone about 0.6m away from the top/front of the PC, which explains the 2 dBA higher readings. This is an unrealistically close distance for a PC in a case as large as the Antec P183, which is designed for placement on the floor; few users would put it on top of the desk.

The source of the increased noise at load was the CPU fan, which went from about 680rpm at idle to 1030rpm at full load. Neither the exhaust or the intake fan changed speed during testing; a calibrated strobe light showed both fans to be spinning at 750~760rpm. The fan in the power supply also did not change speed or noise throughout the testing. At idle, the PC is quiet enough that the ambient noise level in almost any normal room will mask it and make it inaudible. In the anechoic chamber, you have to get within about two feet of the front panel to hear it at all. In a carpeted 20'x10' office, when set atop a desk two feet away from the keyboard and monitor, the noise is audible as a smooth, low level, broadband sound with a touch of tonality in the lower frequencies. When accessed, occasional chatter from the the hard drive can be heard, but at a very low level, with peaks getting no higher than 1 dBA@1m above the norm. Placed on a carpeted floor under a desk, any noise from the PC becomes difficult to discern.


The frequency spectrum of the Serenity shows a bit of a tonal peak at ~90Hz, which is the fundamental frequency of the WD Green hard drive, and another around 200Hz. The overall level is very modest; the highest peak barely crests 0 dBA.


At full system load, the dominant tonal peak is at 150~200 Hz, caused mostly by the CPU cooler fan. The relatively low requency of this peak makes it relatively benign. Most people are much less bothered by lower frequency noise compared to a high frequency noise of the same SPL.

Audio Recording

This recording was made with a high resolution, lab quality, digital recording system inside SPCR's own 11 dBA ambient anechoic chamber, then converted to LAME 128kbps encoded MP3s. We've listened long and hard to ensure there is no audible degradation from the original WAV files to these MP3s. It represents a quick snapshot of what we heard during the review.

  • Puget Serenity PC — System at idle, 14 dBA@1m, and at full CPU/GPU load, 18 dBA@1m

The recording starts with 7 seconds of ambient noise, followed by 10 second segments at various states. For the most realistic results, set the volume so that the starting ambient level is barely audible, back the volume control off a touch to make it just inaudible, then don't change the volume setting again while comparing all the sound files.

2. Cooling

The temperatures of the various components stayed ridiculously low throughout the testing. Despite its low noise, this PC is very well cooled. There is at least 15°C headroom for every component; in other words, even at 35°C ambient temperature, all the components would remain cool enough to keep running at full load. Under such conditions, the CPU fan can be expected to rise beyond 1030rpm, as it is controlled by the Q-Fan controller in the BIOS of the Asus motherboard, set to "Silent" mode. Exactly how much louder it will get is not possible to determine without a hot room capable of 35°C. Suffice it to say the overall noise cannot go above ~25 dBA@1m, which is the measured system SPL when the CPU fan is set manually to its maximum speed of ~1,500rpm. Puget expressly states that this PC is designed for quiet operation in an ambient of up to 30°C.

3. Power

The idle state AC power consumption of 70W is fairly modest for a system with the computing power of an Intel i7-860 CPU and the graphics capability of the ATI HD5750, a mid-level gaming card. While the maximum CPU/GPU load power of 240W will not win any green prizes, it's apropos for a system with these components. The AntecCP-850's efficiency is shy of the best, but it's quite good, nearly 85% at the 240W AC power draw level (according to our own review). More moderate use, such as playing a 1080p HD video, barely riased the power level 15W over the idle.

4. Performance

No conventional performance benchmarks were run on the system. The high performance characteristics of the Intel i7-830, the ATI HD5750 video card and the Intel SSD are all very well documented in dozens of tech web sites. For reference sake, the Windows Experience Index was a high 7.3. There were no problem of any kind encountered during our testing. Windows 7 Home Premium 64-bit provides a mature, smoothly operating environment, with full access to the 4 GB of installed RAM. The quick boot time of under 35 seconds (from power button press to actual usability at the desktop) made possible by the Intel SSD was nice to see, as well as the effective and quick sleep mode, where the minuscule 3.4W power draw makes powering the system off/on almost completely unnecessary.

CONCLUSIONS

The Puget Serenity is a welcome addition to SPCR-certified silent PCs. It is a carefully crafted high performance computer that compares well with any other computer of similar components in mid-2010, with an acoustic footprint that is very small. The noise of this system will hardly be audible in many environments, and certainly not in any ordinary office. At the same time, the Serenity is as well cooled as any PC around, which bodes well for a long and stable usable life.

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Serenity PC page at Puget Custom Computers
Serenity SPCR Edition
The SPCR-certified Silent PC Program

The Serenity SPCR Edition has been improved with no increase in price. It is amazingly, substantially quieter than the original reviewed above — already a very quiet machine. See the new review here: Puget Serenity, SPCR Edition v.2

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Comment on this article in the SPCR Forums.



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